543 
Wheat under Different Conditions of Growth. 
over 45 0 F. Also an extra amount of sunshine occurred just at this time, 
82-5 hours for the week (the maximum for the whole season), and this may 
have helped to cause such a striking and sharply marked change. 
grm. 
Field Trials. 
Methods used by earlier workers. Various methods of root investigation 
have been devised at different times, the most straightforward being to 
wash out the roots by means of a jet of water under pressure. Hays, 1 
working at Minnesota in 1889, used this method and was able to obtain 
useful information on the development of the roots of maize plants. A few 
years later, 2 1893, he used a more complicated method by which he was 
able to extricate the plant with its roots in almost the exact position in 
which they grew. This was done by means of a frame made of 1 in. gas- 
pipe, which was sunk into a hole just large enough to take it. The frame 
1 Hays, W. M. : Com, its Habits of Root Growth . . . Suckers. Agr. Expt. Sta., Univ. 
Minnesota, Bull. 5, pp. 5-33, 1889. 
2 Ibid. : A Device for Illustrating the Root Growth of Plants. North Dakota Sta., Bull. 10, 
PP- 47-9. PI- h 1893. 
N n 2 
